Heretofore, as charging methods for an electric vehicle, there have been known contact type charging for charging an electric vehicle by having a charging nozzle connect to the electric vehicle while the electric vehicle is stopped, and non-contact charging for charging the electric vehicle through magnetic forces in a non-contact state.
In the former method, even in the case of a comparatively fast rapid charging system, with currently installed charging devices, time on the order of thirty minutes is required until the electric vehicle becomes fully charged, and the usefulness of such charging devices is low in comparison with gasoline-powered vehicles.
Although the latter non-contact charging method carries out charging through magnetic forces, problems have existed in that the charging power is lower as the influence of magnetic forces on the exterior must be taken into consideration, or investment costs in infrastructure become high due to complexity of the technology and equipment.
Notwithstanding, practical use of an electric vehicle is urgently needed from the standpoint of environmental issues, and there has been a demand to develop at an early stage an electric vehicle having the same level of convenience as a gasoline-powered vehicle.
Thus, as disclosed in Japanese Laid-open Patent Publication No. 2006-246568 and Japanese Laid-open Patent Publication No. 2001-128304, in order to enhance the convenience of the electric vehicle, techniques have been proposed for charging during traveling of the vehicle. However, all of these techniques are in a conceptual phase, and heretofore none of them have actually been studied deeply and embodied in detailed form.
Further, as techniques that are comparatively close from the standpoint of enabling charging during traveling and for which progress is notable, techniques for hybrid (electric) trains exist, as disclosed in Japanese Laid-open Patent Publication No. 2008-263741 and Japanese Laid-open Patent Publication No. 2009-171772. In such techniques, a vehicle or a train that travels on a track travels along an electrified section and a non-electrified section. In addition, within the electrified section, charging of a vehicle-mounted energy storage device is carried out while the vehicle is traveling with electrical power from aerial power lines, whereas within the non-electrified section, the vehicle travels with charged power from the energy storage device.
However, in the case that the vehicle is traveling on a track, the electrified section is constructed on the assumption that traveling of the vehicle occurs at a predetermined vehicle speed roughly from the beginning to the end thereof. Therefore, in order to enable full charging of the energy storage device within the electrified section, in accordance therewith, the lengths of the electrified section and the non-electrified section, and the charging speed should be set appropriately.
However, the charging time is not assured under an environment such as when traveling takes place on a trackless trajectory, in which the vehicle speed within the electrified section and contact with and separation away from the power lines are controlled in accordance with the intentions of the driver. Therefore, the ideas differ fundamentally, and it has not been possible to simply put to use the technology of hybrid trains.
In view of this situation, the present applicant has proposed the technique disclosed in Japanese Laid-Open Patent Publication No. 2013-208008 (hereinafter referred to as “JP2013-208008A”). With the power supplying control of JP2013-208008A (see FIGS. 4 through 6), prior to a power receiving arm AM coming into contact with power line contact terminals CT, i.e., “II: immediately before supply of power”, a pre-charging process is carried out. Further, after the power receiving arm AM has contacted the power line contact terminals CT, i.e., upon “III: initial of supply of power”, a current that flows in a high voltage battery 24 (battery current Ib) is controlled so as to increase gradually. Thereafter, i.e., upon “IV: supply of power”, an external power supplying portion 12 and the high voltage battery 24 are directly connected to each other.